CK quick screw connectors made of brass, plastic or aluminium are suitable for collecting plastic lies with defined hose inside and outside diameter combinations. These screw connections are used where push-in fittings cannot be practically used due to technical basic conditions (e.g. for very soft hoses, vacuum applications, liquids or for strong movements between hose and connection). As a rule these connections are used with hoses made of polyurethane (flexible), polyamide (stable), PE (economical, but kink sensitive) or PTFE (highly resistant). Colloquially these screwed connections are often called quick screw connectors or CK screw connectors.